Effect of Drying Methods on Chemical Profile of Chamomile (Matricaria chamomilla L.) Flowers

Abstract

Chamomile (Matricaria chamomilla L.) is used in the food industry, stomatology, pharmacy, and medicine due to the beneficial properties of chamomile flowers, which are due to the content of terpenoids, but also flavonoids and phenolic acids. This study aims to determine and compare the effects of the drying method on the metabolic profile of chamomile flowers from sustainable, organic practice. The flowers were dried using four different methods: in the sun at a temperature of around 30 °C for 4 days, in the shade at an average temperature of 20–25 °C for 7 days, in a dryer at a temperature of 105 °C for 24 h, and in a climate chamber at a temperature of 60 °C for 48 h. The drying method affects the color, aroma, dry biomass, and chemical profile of chamomile flowers. The biggest color change was between fresh chamomile flowers and chamomile flowers dried in a climate chamber at 105 °C for 24 h, and the smallest change was observed in flowers dried in the sun. The highest contents of polyphenolic compounds and antioxidant activity were measured in flower samples dried in the sun. Drying the flowers at 105 °C caused a significant decrease in total phenols and total flavonoids compared to the drying methods in the sun and shade. Drying at 60 °C for two days had the most significant negative effect on polyphenolic compounds. GC-MS analysis of chamomile essential oil revealed a total of 49 compounds. The most abundant compounds in all samples were α-bisabolol oxide A (19.6 to 24.3%), bisabolol oxide B (19.3 to 23.2%), and β-farnesene E (15.9 to 25.5%). β-Farnesene was identified in significantly lower amounts in sun-dried flowers compared to others, indicating its sensitivity to high light intensity. Volatile compounds spiroether Z, spiroether E, and matricarin were significantly reduced in samples dried at a temperature of 105 °C compared to others, which agrees with the aroma of dried flowers. Discrimination between samples based on chemical profiles showed similarity between samples dried in the sun and in the shade compared to samples dried at higher temperatures.